Unusual Chantal Disorganized, but has 65 mph Winds

By: Dr. Jeff Masters , 8:06 PM GMT on July 09, 2013

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Unusual Tropical Storm Chantal has strengthened a bit more as it speeds west-northwestwards at 26 mph away from the the Lesser Antilles Islands. Sustained winds of 38 mph, gusting to 52 mph, were observed at Martinique at 10 am AST as the storm passed. However, an automated weather station at the airport measured sustained winds of 60 mph, gusting to 78 mph, according to an official with Meteo-France. The Associated Press reported that Chantal ripped the roofs off of several homes on neighboring Dominica. An Air Force hurricane hunter aircraft measured top winds at their 1,000' flight level of 89 mph at 12:55 pm AST. Top winds seen by the aircraft's SFMR instrument were about 65 mph, in a small area east of Chantal's center. The Hurricane Hunters have departed Chantal, and the next plane is due in the storm at 8 pm EDT. Chantal's winds are unusually high considering the storm's high central pressure of 1006 mb and disorganized appearance on satellite imagery. Chantal is fighting dry air associated with the Saharan Air Layer (SAL), as seen on water vapor satellite loops. This dry air is creating strong thunderstorm downdrafts that are robbing Chantal of moisture and energy. Visible satellite loops show the outflow boundaries of these thunderstorm downdrafts at the surface, spreading to the northwest of Chantal. Martinique Radar shows a large area of heavy rain that is not well-organized, lying mostly to the west of the Lesser Antilles Islands.


Figure 1. MODIS image of Chantal taken at approximately 1 pm EDT Tuesday, July 9, 2013. At the time, Chantal had top winds of 65 mph, but looked very disorganized, due to high wind shear and dry air. Dry air is creating strong thunderstorm downdrafts that are robbing Chantal of moisture and energy. Outflow boundaries from these downdrafts are spreading out to the northwest of Chantal, as seen on this satellite image. Image credit: NASA.

An small-scale easterly jet creating high shear in Chantal
Chantal is not very impressive on satellite images, with a modest amount of heavy thunderstorms that are not well-organized. Only a small amount of upper-level outflow is visible. The reason for Chantal's rather disorganized appearance can be found by looking at this morning's balloon sounding from Guadaloupe. This island was just northwest of the center of Chantal when the balloon was launched at 8 am EDT. The sounding showed typical easterly trade winds at the surface of 12 knots (14 mph.) However, the winds rose quickly aloft, with a jet of easterly winds of 35 - 53 knots between 800 - 600 mb (about 7,000 - 15,000'.) But, by the time the ballon hit 500 mb (18,000'), the winds had died down to 15 knots. A change of wind speed from 12 knots to 53 knots and back down to 15 knots from the surface to 500 mb is a tremendous amount of wind shear, which will make it very difficult for a tropical storm to keep the surface center aligned with the upper level center. The traditional measure of wind shear, the difference in wind between 200 mb and 850 mb, was 44 knots in this morning's Guadaloupe sounding, but was a much higher 56 knots from 200 mb to 700 mb. The powerful easterly wind jet was not apparent at any of the other balloon soundings this morning at adjacent islands (Barbados, Puerto Rico, Saint Martin), and demonstrates that there is a lot going on the atmosphere at small scales we cannot see which makes intensity forecasting of tropical cyclones very challenging. Thanks go to Jason Dunion of NOAA's Hurricane Research Division for pointing out this morning's interesting Guadaloupe sounding.

Forecast for Chantal
Chantal will have difficulty intensifying much more before hitting Hispaniola on Wednesday afternoon. In their 11 am EDT wind probability forecast, NHC gave Chantal a 29% chance of becoming a hurricane before hitting Hispaniola. Working against intensification will be the high wind shear from the strong mid-level easterly jet discussed above, plus the fast forward speed of the storm--tropical storms moving faster than 20 mph in the deep tropics usually have trouble intensifying. In addition, the Eastern Caribbean is an area where the trade winds accelerate, helping drive sinking air that discourages tropical storm intensification. Dry air will also slow down the intensification process. Interaction with the high mountains of Hispaniola and high wind shear may be able to destroy Chantal by Thursday. The 2 pm EDT Tuesday wind shear forecast from the SHIPS model calls for shear to rise to the high range, 20 - 35 knots, Tuesday night through Friday. On Saturday, when Chantal is expected to be in the Bahamas, moderate wind shear of 10 - 20 knots is predicted. If Chantal survives until Saturday, it will then have the opportunity to re-strengthen. The latest 12Z run of the European model (ECMWF) dissipates Chantal as it crosses Hispaniola. The 12Z run of the American GFS model has Chantal barely surviving.

Chantal's fast west-northwest forward speed of 26 mph will slow to 20 mph by Wednesday morning and then 10 mph by Thursday night, as the storm "feels" the presence of a trough of low pressure over the U.S. East Coast. This trough will steer Chantal to the northwest and then north-northwest across Hispaniola and into the Bahamas. The trough of low pressure pulling Chantal northwards is expected to lift out the the northeast over the weekend, leaving Chantal behind off the coast of Florida. High pressure will likely build in, potentially forcing Chantal westwards into the Florida or Southeast U.S. coast, with a possible Sunday landfall.

Jeff Masters

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Quoting 2216. SFLWeatherman:
Look at SE FL!!


It's Grothar's other blob.

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26 west!!
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Quoting 2219. pcola57:
Current LSU seasonal SST outlook..

If Chantal crosses Cuba just E of Havana, it will have avoided the worst of the mountains and will emerge over the best SST in the area... as long as some circulation survives, there is at least some possibility of regeneration in this area. Especially if it then proceeds up the Gulf Stream, there may even be some possibility of intensification before final landfall. This would make a very interesting finale to what has been an interesting storm to watch.

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Quoting 2230. GeoffreyWPB:

Blowing back up huh?
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2232. Grothar
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Quoting 2222. BahaHurican:
Hmmm.... still suggesting possibility of heavy rains to the PortauPrince area... :o(

This needs to keep moving west very quickly indeed.

Yes, but the energy is relocating to her north and perhaps forming another center. bbl
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Member Since: September 10, 2007 Posts: 0 Comments: 10992
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Do we have a new AOI.
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Quoting 2224. hurricanes2018:
I am calling it Tropical wave CHANTAL now..

It's holding together...
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Quoting 2182. StormJunkie:
Chantal at her strongest according to the 6z GFDL



And the HWRF...A whopping 26kts...





What up SJ? Yea, looks like Chantal is a mess. We will still see a bout of heavy rain this weekend here in the Lowcountry. Deep tropical moisture (not directly associated with whats left of Chantal) and a stalled front will produce locally heavy rains - AGAIN !! This pattern looks brief, however. Not the 2 week setup we saw at the end of June.
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Quoting 2182. StormJunkie:
Chantal at her strongest according to the 6z GFDL



And the HWRF...A whopping 26kts...





What up SJ? Yea, looks like Chantal is a mess. We will still see a bout of heavy rain this weekend here in the Lowcountry. Deep tropical moisture (not directly associated with whats left of Chantal) and a stalled front will produce locally heavy rains - AGAIN !! This pattern looks brief, however. Not the 2 week setup we saw at the end of June.
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I am calling it Tropical wave CHANTAL now..
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2223. JRRP
the perfect link
Link
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Quoting 2202. Chicklit:
This WU map shows the heaviest concentration of energy a little SE of Cape Beata

Hmmm.... still suggesting possibility of heavy rains to the PortauPrince area... :o(

This needs to keep moving west very quickly indeed.
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good morning, i see chantal is now a wave. what did you expect in early july from a storm moving 30mph? wait til august when we get our next wave train. could get monsters likein the westpac
Member Since: July 25, 2011 Posts: 0 Comments: 1102
The floater page isn't updating for me anymore.
But it updates on WU ground!



hmmm shortwave doesn't. everything on nhc floater site is still back at 10:15 UTC
Correct that (I thought they were still down at 15.5)
BASED ON 0600 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 1015 UTC.

...SPECIAL FEATURES...
TROPICAL STORM CHANTAL IS CENTERED NEAR 16.5N 70.8W AT 10/1200 UTC OR ABOUT 132 NM SSW OF SANTO DOMINGO DOMINICAN REPUBLIC MOVING W AT 25 KT.
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2219. pcola57
Current LSU SST ..



EDIT: I see something wrong here..
Will correct momentarily
OK..Better now..
Current SST from LSU..
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2218. Dakster
Quoting 2215. JrWeathermanFL:
@2192
At the NHC....
"Avila go fetch the crayon box"


That is the JUNIOR weatherman's job...
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2217. flcanes
Quoting 2214. Dakster:


Nothing that wasn't forecasted as a possibility. In fact, at this point it might dissipate when it hits the mountains.

Ok....
Back to lurking...
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Look at SE FL!!
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@2192
At the NHC....
"Avila go fetch the crayon box"
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2214. Dakster
Quoting 2210. flcanes:

No but as in intensity wise, dropping 20 mph and almost an open wave?


Nothing that wasn't forecasted as a possibility. In fact, at this point it might dissipate when it hits the mountains.
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Quoting 2147. BahaHurican:
Finally getting some breakfast... whole wheat pancakes with dates and raisins, maple syrup, and, of course coffee...


Leftover potato pancakes.. latke to some, sausage, ripe tomato, over easy eggs and coffee.. mmm mmm

That is a very good image Gro, most excellent post.(2145)

2152 is another excellent example, well done!
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2212. Grothar
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2211. FOREX
Quoting 2192. GeoffreyWPB:
If Chantal is an open wave, the question is what color crayon will the NHC use at 11am?
invisible ink
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2210. flcanes
Quoting 2209. Dakster:


10 Hours passed, tracks changed...

No but as in intensity wise, dropping 20 mph and almost an open wave?
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2209. Dakster
Quoting 2206. flcanes:
Hi.
Can somebody explain to me what happened between 10 pm last night and 8 am this morning?


10 Hours passed, tracks changed...
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Quoting 2201. palmpt:


Don't lecture Taz...


Thanks for your input!

Have a great day.
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2207. bigtp3
Wow, surprising change of track since yesterday...
If it does stay on the present track it'll probably stay at TD status after going through Cuba and such. But when it hits the FL Straits we can never rule out some sort of strengthening. After we saw what Katrina did, just off of FL in such little time, you can't ever be too careful.
Here comes some more rain for SoFla. Wish we could send some to y'all who actually need it!
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2206. flcanes
Hi.
Can somebody explain to me what happened between 10 pm last night and 8 am this morning?
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Quoting 2183. Tazmanian:




i dont want too see is freaking commets and your not being funny at all the olny thing you are freaking doing is feeding a troll that many of us had too put on Ignore he was be so annyouing on sunday with his commets and he is still doing the same today that many of us had too put him on Ignore

Take a breath and quit acting like a troll Taz. Your comments are doing the blog more harm than good. No one else is bickering

Meanwhile its 80 degrees with 92% humidity from sticky NOLA
Good morning all
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Should be west winds here, she's a wave.


Coordinates: 15.5N 71.4W
Location: 219 miles (353 km) to the SSE (164°) from Port-au-Prince, Haiti.
Turbulence: None
Conditions Along Flight Route: In the clear
Pressure Altitude: 360 meters
Flight Level Wind: From 110° at 16 knots (From the ESE at ~ 18.4 mph)
- The above is a spot wind.
- Winds were obtained using doppler radar or inertial systems.
Flight Level Temperature: 20°C
Flight Level Dew Point: 20°C
Weather (within 30 nautical miles): Thunderstorm(s)
Mean Sea Level Pressure (MSLP): 1014 mb (extrapolated)

Optional Data...

Estimated Surface Wind: From 90° at 10 knots (From the E at ~ 11.5 mph)
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2203. pcola57
Quoting 2187. Tazmanian:




this is more updated




I see 0400utc on yours and 0600utc on my post..
Find something else to gripe about..
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2201. palmpt
Quoting 2185. seminolesfan:


Taz, you jumped all up in someone's business yesterday for someone saying not to quote you because of the same reason.

Now today, with the shoe on the other foot, you find it completely appropriate to tell someone else to not quote someone.

As much as you would love to be one; You are not a mod.

Stop with the blog police nonsense. It is very tiring to see you not following the 'rules' you hold other posters to...


Don't lecture Taz...
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Quoting 2194. ProgressivePulse:
No West winds so far.
She is gone for now.
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Quoting 2185. seminolesfan:


Taz, you jumped all up in someone's business yesterday for someone saying not to quote you because of the same reason.

Now today, with the shoe on the other foot, you find it completely appropriate to tell someone else to not quote someone.

As much as you would love to be one; You are not a mod.

Stop with the blog police nonsense. It is very tiring to see you not following the 'rules' you hold other posters to...




if you dont like my commets then put me on ignore and move on you dont need too keep saying the same old crap evere day you come on here put me on ingore and be done with it that gos for the same too the rest of you if you dont like what one of my commets this ! and ingore them then haveing too start up a big oh fight overe nothing i think the mods told you guys this 100s of times now and you guys still dont do it
Member Since: May 21, 2006 Posts: 5091 Comments: 114756
Quoting 2155. bdm2225:
Approaching hurricane strength, now maybe open tropical wave. Dying storm, now popping convection again. She can't decide what she wants to do and where she wants to go, but us here in Port-au-Prince would like to know ASAP! Any ideas?
Stay under cover today??? It's looking like maybe the worst will stay off shore while Chantal tries to get its act together, but better safe than sorry...

Welcome to the blog, BTW... haven't seen you posting much in here before...

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Quoting 2193. RTLSNK:
Good Morning everyone,

Lets all talk about the storm,

And not about each other.

Thanks.


10-4, Rattlesnake! :)
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2196. Dakster
Quoting 2145. Grothar:
This shows the weakness where the system could begin turning.




Interesting Gro - Looking like a Florida Storm with that graphic.
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2195. WxLogic
Pretty good confirmation from recon that is poof. No more NHC updates after this.
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No West winds so far.
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2193. RTLSNK
Good Morning everyone,

Lets all talk about the storm,

And not about each other.

Thanks.
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If Chantal is an open wave, the question is what color crayon will the NHC use at 11am?
Member Since: September 10, 2007 Posts: 0 Comments: 10992
2191. Relix
The wave off CV is supposed to be "Dorian" right? I know the models backed off but hey, they didn't pick up Chantal. These caribbean trackers will be my bane :P
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Quoting 2148. washingtonian115:
That wave off Africa is more interesting then Chantal and vorticity is starting to stack.I wonder when the NHC will high light it.Thats the real threat there.
How can you dis Chantal like that???

lol

I'm glad we had Chantal to break the ice. I must say we mostly behaved quite well... only a couple of troll attacks... lots of good tracking.

On the next Twave, I see GFS has lost it... which means it's pretty likely to spin up, at least nominally, at some point. I doubt we're done w/ Chantal quite yet - storms have opened out in this area, only to regenerate further down the road - but I agree w/ u and 2018 that we need to be keeping an eye on the next wave.
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2189. FOREX
Quoting 2027. StormTrackerScott:
Folks don't count Chantal out yet as there is almost no shear close to fl. Chantal has been fighting some westerly shear the last 24 hours but once Chantal emerges in the sw Atlantic then conditions will be very favorable for regeneration.


You nailed Andreas forecast so I ask you if this could miss Cuba completely and come into the central or eastern gulf and strengthen?
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Quoting 2178. pcola57:


Morning Washi..

This is the suppose Dorian that now models have back off?Hope is not another fail like Chantal.
Quoting 2179. hurricanes2018:
its more like Tropical wave CHANTAL!!
Reminds me of Chantal of 2001 it degenerate into a tw and then regenerate.
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Quoting 2178. pcola57:


Morning Washi..





this is more updated


Member Since: May 21, 2006 Posts: 5091 Comments: 114756
They do have south winds at 16.0W 70.8N

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Jeff co-founded the Weather Underground in 1995 while working on his Ph.D. He flew with the NOAA Hurricane Hunters from 1986-1990.

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